PROJECT 3 ABSTRACT (PROJECT DESCRIPTION) Asthma exacerbations lasting for weeks occur in 25-50% of children with asthma each year in Southern Califor- nia. Remarkably, ozone and particulate matter (PM) may account for as much as 70% of bronchitis-related ex- acerbations in the polluted communities studied in the landmark Children?s Health Study (CHS). Given the clinical and public health burden from asthma exacerbations, there is a clear need for improved prevention and clinical management approaches. The Los Angeles PRISMS Center will develop a system to advance the scientific understanding of asthma symptoms and exacerbations as well as deliver timely, personalized interventions and treatments to support self-management activities, promote adherence, and provide active feedback to patients, caregivers, clinicians, and researchers. In this U54 application, we propose to develop and test an integrated asthma management platform, the Bio- medical REAl-Time Health Evaluation for Pediatric Asthma (BREATHE). The broad objectives of Project 3 are to develop, assess performance, and test field protocols for the integrative BREATHE platform; to improve sci- entific understanding of asthma exacerbations; and to develop risk prediction models using real-time data on determinates of exacerbations. To meet these objectives, we propose the following specific aims for this appli- cation: 1) to evaluate field performance of the BREATHE platform in key microenvironments including accuracy and precision of highly resolved spatial and temporal data for exposure assessment, reliability and validity of asthma outcomes and psychosocial variables (e.g., stress); 2) to develop and test field protocols for use of BREATHE in longitudinal studies of 8-12 year old children with asthma, including potential PRISMS U01 sensors; 3) to assess usability of BREATHE for children with asthma and their caregivers, for clinicians, and for research- ers including iterative refinement of protocols and the user interfaces; 4) to increase scientific understanding of the contextual real-time determinants of asthma exacerbations; and 5) to enhance a risk prediction model by incorporating real-time contextual data and analytics to provide actionable information for personalized self- management and prevention of exacerbations among children with asthma. The participants for Project 3 will be recruited from the UCLA Pediatric Asthma Clinic. Efforts in Project 3 are thus closely coordinated with the tech- nical developments in Projects 1 & 2 to ensure a usable end-to-end platform. Our anticipated outcome is a well- characterized and operational prototype demonstrating BREATHE, with great potential for supporting PRISMS and future pediatric biomedical research.